Mix 1/4 cup of chocolate syrup into the soy milk. Pour into an ice cube tray. Freeze until solid or almost-solid.
Put soy cubes into a food processor. Add raspberries and chocolate chips. Drizzle with the remaining chocolate syrup. Blend until smooth. Add a tiny bit more soy milk if necessary to make blending easier.
Serve immediately, garnished with fresh raspberries and mint sprigs if you have them.